Clinical information on the regional myocardial blood flow in the post-ischemic myocardium has been limited. In the present study, we assessed the influence of early coronary reperfusion and coronary obstruction that remained after reperfusion on regional myocardial perfusion by myocardial contrast echocardiography. The study population consisted of 17 patients with acute myocardial infarction who underwent either successful PTCR or emergent PTCA within 6 hours after the onset of the symptom. Myocardial blood flow was visualized by selective injections of hand-agitated polygelin colloid solutions into the right and left coronary arteries before and after coronary reperfusion. Before coronary reperfusion, the area at risk for necrosis was defined as the area of contrast defects by the intracoronary injection of contrast medium. The size (severity) of this defect correlated with the anatomic distribution of the obstructed coronary artery. Immediately after emergent PTCA (mean residual stenosis=25%), 2 of 10 patients still showed injected contrast medium, however, in the remaining 8 patients (80%), the contrast washout time in the risk area was 1.5 times (mean value) longer than that in the normal region. This indicated impairment of the microcirculation in the postischemic myocardium. Immediately PTCR (mean residual stenosis =89%, p<0.01 vs PTCA), contrast enhancement was observed only in the peripheral region of the risk area; contrast defects at the center of this region were observed on contrast echocardiography after reperfusion for all patients. This showed that there was impairment of myocardial blood flow in the risk area, even after successful recanalization in patients undergoing PTCR. The difference in myocardial perfusion dynamics after PTCR and PTCA may be attributed to the difference in severity of the residual coronary stenosis. Thus, post-ischemic myocardial perfusion seems to be affected not only by the residual stenosis but also by the impairment of the myocardial microcirculation.
|Number of pages||9|
|Journal||Journal of cardiology|
|Publication status||Published - 1991|
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine